A housing for the SBM-19 Geiger tube, with room for electronics board, and battery pack. See the project here for how to make the circuit board:
Assembly instructions: This unit must be printed in four pieces due to it's size. The bottom pieces must be glued together, and the top pieces together. Once this is done, the electronics board can be mounted, the battery pack, and the GM tube. The top and bottom can be fastened together by using four M4 nuts and bolts.
The battery holder can be found on ebay by searching for "2 aa battery holder". The type with no lid, and two lying side-by-side is needed for this model.